Joint mechanism, manipulator, and manipulator system

ABSTRACT

Provided is a joint mechanism including a tubular first member having a through-hole; a second member disposed at the distal end of the first member and swivelable about a swivel axis intersecting a central axis thereof; a flexible, tubular guide sheath extending near the central axis of the through-hole and a distal end of which is fixed to the second member; a manipulation wire introduced toward the distal end of the guide sheath; and a turnaround section that is provided in the second member at a position decentered from the swivel axis in the radial direction and that causes the manipulation wire introduced from the first member via the guide sheath to make a U-turn toward the first member. A distal end of the manipulation wire caused to make a U-turn at the turnaround section is fixed to a position decentered in the radial direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of International Application PCT/JP2015/050541,with an international filing date of Jan. 9, 2015, which is herebyincorporated by reference herein in its entirety. This applicationclaims the benefit of Japanese Patent Application No. 2014-004376, thecontent of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to joint mechanisms, manipulators, andmanipulator systems.

BACKGROUND ART

In the related art, a known medical device has a multi-joint bendingmechanism in which a plurality of bending segments connected in aswivelable manner are independently and individually manipulated bymeans of manipulation wires (for example, see Patent Literature 1).

In this multi-joint bending mechanism, a position close to the outerperiphery of each bending segment is pulled toward the basal end byusing each manipulation wire so as to generate moment. Therefore, inorder to efficiently transmit a traction force to the bending segments,the manipulation wires and tubular guide sheaths that guide themanipulation wires are routed so as to extend along paths locatedrelatively close to the outer peripheries of the bending segments.

Furthermore, in the multi-joint bending mechanism in Patent Literature1, the manipulation wire connected to the bending segments locatedcloser toward the basal end is disposed at the inner side, in the radialdirection of the bending segments, relative to the manipulation wireconnected to the bending segments located closer toward the distal end.By applying a traction force to the manipulation wires, each bendingsegment swivels relative to the other bending segments, thus causing themanipulation wires and the guide sheaths to bend.

CITATION LIST Patent Literature

{PTL 1}

The Publication of Japanese Patent No. 5197980

SUMMARY OF INVENTION Technical Problem

The present invention provides a joint mechanism, a manipulator, and amanipulator system that can achieve bendability with a small tractionforce, reduced device size, and improved controllability.

Solution to Problem

A first aspect of the present invention provides a joint mechanismincluding a tubular first member having a through-hole extending along acentral axis; a second member disposed at a distal end of the firstmember and swivelable relative to the first member about a swivel axisintersecting the central axis; a flexible, tubular guide sheathextending near the central axis of the through-hole in the first memberand a distal end of which is fixed to the second member; a manipulationwire introduced toward the distal end of the guide sheath via the guidesheath; and a turnaround section that is provided in the second memberat a position decentered from the swivel axis in a radial direction andthat causes the manipulation wire introduced from the first member viathe guide sheath to make a U-turn toward the first member. A distal endof the manipulation wire caused to make a U-turn at the turnaroundsection is fixed to the first member at a position decentered from theswivel axis in the radial direction.

A second aspect of the present invention provides a manipulatorincluding two or more series-connected joint mechanisms described above.

A third aspect of the present invention provides a manipulator includinga tubular manipulator body, a basal-end joint unit provided at a distalend of the manipulator body, and a distal-end joint unit connected inseries to a distal end of the basal-end joint unit and equipped with atleast one joint mechanism described above. The basal-end joint unitincludes a swivel member connected to the manipulator body in aswivelable manner about a swivel axis, a tubular guide sheath whoseopening at a distal end thereof is fixed to the manipulator body, and amanipulation wire that is introduced via the guide sheath and protrudesfrom the opening at the distal end of the guide sheath and a distal endof which is fixed to a position decentered from the swivel axis of theswivel member in a radial direction.

A fourth aspect of the present invention provides a manipulatorincluding a tubular manipulator body having a through-hole extendingalong a central axis; a swivel member disposed at a distal end of themanipulator body and swivelable relative to the manipulator body about aswivel axis intersecting the central axis; a flexible, tubular guidesheath extending near the central axis of the through-hole in themanipulator body and a distal end of which is fixed to the swivelmember; a manipulation wire introduced toward the distal end of theguide sheath via the guide sheath; and a turnaround section that isprovided in the swivel member and that causes the manipulation wireintroduced from the manipulator body via the guide sheath to make aU-turn toward the manipulator body. A distal end of the manipulationwire caused to make a U-turn at the turnaround section is fixed to themanipulator body at a position decentered from the swivel axis in theradial direction.

A fifth aspect of the present invention provides a manipulator systemincluding the above-described manipulator, a slave device equipped witha driver that drives the manipulator, a master device equipped with anoperation section to be operated by an operator, and a controller thatcontrols the driver of the slave device based on an input signal inputvia the operation section of the master device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates the overall configuration of a manipulator systemaccording to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a slave device equipped withan endoscope.

FIG. 3A is a simplified side view of a bendable section of the endoscopein FIG. 2.

FIG. 3B is a schematic side view of a bendable section of the endoscopein FIG. 2.

FIG. 4 is a vertical sectional view illustrating a state where abasal-end joint group of the bendable section in FIG. 3A is extendingstraight.

FIG. 5 is a vertical sectional view illustrating a state where a flexurejoint at the most distal end of the basal-end joint group of thebendable section in FIG. 3A is flexed.

FIG. 6 is an exploded perspective view illustrating a flexure joint atthe most basal end of the basal-end joint group of the bendable sectionin FIG. 3A.

FIG. 7 is a front view of a link member as viewed along a central axis,illustrating the positions of pulleys, guide sheaths, and manipulationwires in the flexure joint in FIG. 5.

FIG. 8 includes a schematic side view and a front view of each linkmember, illustrating the positions of the pulleys, the guide sheaths,and the manipulation wires in the basal-end joint group in FIG. 4.

FIG. 9 is an exploded perspective view illustrating a modification ofFIG. 6.

FIG. 10A illustrates a modification of the positions of the pulleys inFIG. 7 and is a front view showing the link member located closest tothe basal end.

FIG. 10B illustrates a modification of the positions of the pulleys inFIG. 7 and is a front view showing the second link member from the basalend.

FIG. 10C illustrates a modification of the positions of the pulleys inFIG. 7 and is a front view showing the third link member from the basalend.

FIG. 11 is a front view illustrating a modification of the pulleys inFIG. 7.

FIG. 12 illustrates a modification of FIG. 8 and includes a schematicside view and a front view of the link members.

FIG. 13 is a side view illustrating a basal-end joint group in whichflexure joints with different flexing directions are alternatelyarranged.

FIG. 14A is a front view showing the link member located closest to thebasal end in FIG. 13.

FIG. 14B is a front view showing the second link member from the basalend in FIG. 13.

FIG. 14C is a front view showing the third link member from the basalend in FIG. 13.

FIG. 15A illustrates a modification of FIG. 14A and is a front viewshowing the link member located closest to the basal end.

FIG. 15B illustrates a modification of FIG. 14B and is a front viewshowing the second link member from the basal end.

FIG. 15C illustrates a modification of FIG. 14C and is a front viewshowing the third link member from the basal end.

FIG. 16 is a vertical sectional view illustrating a bendable sectionhaving a single flexure joint.

FIG. 17 is a front view illustrating a modification of segments.

FIG. 18 is a front view illustrating another modification of thesegments.

FIG. 19 is a vertical sectional view illustrating a bendable sectionhaving the segments in FIG. 18.

DESCRIPTION OF EMBODIMENTS

A joint mechanism, a manipulator, and a manipulator system according toan embodiment of the present invention will be described below withreference to the drawings.

As shown in FIG. 1, the manipulator system according to this embodimentis an endoscope system 1 and includes a master device 2 to be operatedby a surgeon (operator) A, a slave device 3 driven in accordance with aninput via the master device 2, a controller 4 that controls the slavedevice 3 based on the input to the master device 2, and a monitor 25.

As shown in FIG. 2, the slave device 3 includes an endoscope(manipulator) 5 according to this embodiment, which is to be insertedinto the body cavity of a patient P, and drivers 6 a and 6 b that drivethe endoscope 5.

The endoscope 5 according to this embodiment is a flexible endoscopehaving a flexible, elongated insertion part 7, which is bendable, andincludes an elongated flexible section (manipulator body) 8, a distalend section 9 disposed at the distal end, and a bendable section 10disposed between the distal end section 9 and the flexible section 8.Although a flexible endoscope is described in this embodiment, a rigidendoscope having an elongated rigid section may be used as analternative.

As shown in FIGS. 3A and 3B, the bendable section 10 includes adistal-end joint group 11 and a basal-end joint group 12 for changingthe position and the orientation of the distal end section 9 relative tothe distal end of the flexible section 8. The distal-end joint group 11and the basal-end joint group 12 are arranged side-by-side in thelongitudinal direction of the insertion part 7. FIG. 3A is a simplifiedview of the bendable section 10, and FIG. 3B is a schematic view of thebendable section 10.

The basal-end joint group 12 includes a plurality of, for example, four,flexure joints (joint mechanism) 12 a to 12 d. Each of these flexurejoints 12 a to 12 d is provided between a corresponding pair of linkmembers 13 a to 13 e and is configured to change the relative anglebetween the pair of neighboring link members 13 a to 13 e.

The flexure joints 12 a to 12 d can be independently flexed about axes14 a to 14 d (extending in the Y-axis direction) arranged parallel toone another and spaced apart in the longitudinal direction of theinsertion part 7, that is, the longitudinal-axis direction of the linkmembers 13 a to 13 e. For example, each of the flexure joints 12 a to 12d can be flexed in a flexion-angle range of ±60° so that the entirebasal-end joint group 12 can be flexed by ±240°. The axes 14 a to 14 ddo not necessarily need to be arranged parallel to one another so longas they are arranged side-by-side to allow for flexion.

The flexure joints 12 a to 12 d according to this embodiment will bedescribed below with reference to FIGS. 4 to 7.

First, the flexure joint 12 a located closest to the basal end will bedescribed in detail.

As shown in FIGS. 4 and 5, the flexure joint 12 a includes a link member(first member) 13 a serving as an end of the flexible section 8, a linkmember (second member) 13 b, and a plurality of, for example, four,segments (intermediate members) 15 a to 15 d connected between theselink members.

The link members 13 a to 13 e and the segments 15 a to 15 d areconnected in a relatively swivelable manner about substantially parallelaxes (intermediate axes) 16 a to 16 e. The axes 16 a to 16 e also do notnecessarily need to be disposed parallel to one another so long as theyare arranged side-by-side to allow for flexion.

As shown in FIG. 6, the flexible section 8 and the link members 13 a and13 b are provided with through-holes 17 extending in the longitudinaldirection. The segments 15 a to 15 d are each formed in the shape of aring having a through-hole 18 extending in the thickness directionthrough the middle thereof. The link member 13 b and the segments 15 ato 15 d are each provided with two pairs of connection sections 19 a and19 b for connecting it to the link member 13 a or 13 b or other segments15 a to 15 d disposed on the opposite sides thereof in a relativelyswivelable manner about two of the substantially parallel axes 16 a to16 e. The link member 13 b is constituted of a combination of twocomponents 13 b 1 and 13 b 2.

The flexure joint 12 a according to this embodiment includes two pulleys20 a and 20 b rotatably attached to the link member 13 b; flexible,tubular guide sheaths 21 a and 21 b that extend through the through-hole17 in the flexible section 8 and the through-holes 18 in the segments 15a to 15 d, that are disposed along the vicinity of the central axes ofthe through holes, and whose openings at the distal ends are fixed tothe component 13 b 1 of the link member 13 b; and manipulation wires 22a and 22 b inserted through the guide sheaths 21 a and 21 b from thebasal end of the flexible section 8.

As shown in FIG. 7, the pulleys 20 a and 20 b are attached to the linkmember 13 b at the opposite sides of the axis 16 a, which connects thelink member 13 b and the segment 15 a, in a rotatable manner about axes23 a and 23 b substantially parallel to the axis 16 a. Thus, the pair ofpulleys 20 a and 20 b cause the pair of manipulation wires 22 a and 22 bprotruding from the openings at the distal ends of the pair of guidesheaths 21 a and 21 b disposed near the axis 16 a of the link member 13b to make a U-turn in the reverse direction, thus causing themanipulation wires 22 a and 22 b to return toward the link member 13 aalong respective paths near the outer peripheries of the link member 13b and the segments 15 a to 15 d, which are the most distant from theaxis 16 a in the radial direction.

Each of the segments 15 a to 15 d is provided with a pair ofthrough-holes 24 a and 24 b through which the pair of manipulation wires22 a and 22 b, which have been caused to make a U-turn toward the outerperiphery by the pair of pulleys 20 a and 20 b, extend. After the pairof manipulation wires 22 a and 22 b are turned back in the reversedirection by the pair of pulleys 20 a and 20 b and extend through thethrough-holes 24 a and 24 b in the segments 15 a to 15 d, the endsthereof are respectively fixed to fixation sections 26 a and 26 b of thelink member 13 a.

The other flexure joints 12 b to 12 d have structures identical to thatof the flexure joint 12 a described above. Specifically, each of theflexure joints 12 b to 12 d includes four segments 15 a to 15 d betweena first member, which is defined by one of the link members 13 b to 13 dat the distal end of the remaining one of the flexure joints 12 b to 12d adjacent thereto at the basal end, and a second member, which isdefined by one of the link members 13 c to 13 e adjacent thereto at thedistal end. The guide sheaths 21 a and 21 b, the pulleys 20 a and 20 b,and the manipulation wires 22 a and 22 b in the flexure joints 12 a to12 d are disposed as shown in a simplified view in FIG. 8.

FIG. 5 illustrates the movement of the flexure joint 12 d, which islocated closest to the distal end, in the basal-end joint group 12. Thetwo manipulation wires 22 a and 22 b that are guided to the link member13 e by the two guide sheaths 21 a and 21 b extending in thelongitudinal direction from the basal end of the insertion part 7 to thelink member 13 e at the distal end of the flexure joint 12 d are causedto make a U-turn by the pulleys 20 a and 20 b and are fixed to thefixation sections 26 a and 26 b in the link member 13 d at the basal endof the flexure joint 12 d. From the state shown in FIG. 4 in which theflexure joints 12 a to 12 d are all extending straight, a traction forceF is applied to the manipulation wire 22 a, as shown in FIG. 5, so thatthe distal-end flexure joint 12 d alone can be flexed in one direction.In this case, the manipulation wire 22 b is fed by an amount necessaryfor the flexion.

As shown in FIG. 3A, the distal-end joint group 11 includes a pluralityof, for example, three, flexure joints (distal-end flexure joints) 11 ato 11 c. Each of these flexure joints 11 a to 11 c is similarly disposedbetween a corresponding pair of link members 13 f to 13 h and isconfigured to change the relative angle between the pair of neighboringlink members 13 f to 13 h.

As shown in FIG. 3A, the two flexure joints 11 a and 11 b closer towardthe basal end are configured to cause the link members 13 f to 13 h toswivel about axes 14 e and 14 f (which extend in the Z-axis direction)orthogonal to a plane that includes the axis 14 d of the flexure joint12 d at the most distal end of the basal-end joint group 12 and the longaxes of the link members 13 e to 13 h. Furthermore, the flexure joint 11c at the most distal end causes the distal end section 9 to swivel aboutan axis 14 g (which extends in the Y-axis direction) orthogonal to aplane that includes the axes 14 e and 14 f of the flexure joints 11 aand 11 b and the long axes of the link members 13 e to 13 h. The axes 14e and 14 f do not necessarily need to be orthogonal to the plane thatincludes the axis 14 d and the long axes and may alternatively intersectthe plane to allow for flexion.

The manipulation wires 22 a and 22 b used for moving all of the flexurejoints 11 a to 11 c and 12 a to 12 d are introduced to the bendablesection 10 from the basal end of the flexible section 8 via thethrough-hole 17 in the flexible section 8.

As shown in FIG. 2, the drivers 6 a and 6 b include two drivers, namely,a distal-end driver 6 a for driving the distal-end joint group 11 and abasal-end driver 6 b for driving the basal-end joint group 12. Thedrivers 6 a and 6 b are connected to the flexible section 8 of theendoscope 5 via a relay unit 27.

The drivers 6 a and 6 b are equipped with sliders (not shown) that areattached to the basal ends of the manipulation wires 22 a and 22 b,which extend toward the basal end through the interior of the flexiblesection 8, so as to pull the basal ends of the manipulation wires 22 aand 22 b and adjust the traction force F to be applied individually tothe manipulation wires 22 a and 22 b. The drivers 6 a and 6 b areattachable to and detachable from drive sources 28 equipped withelectrically-driven actuators or manually-operated masters (not shown)of the manually driven type.

The actuators of the drive sources 28 are, for example, linearactuators, such as linear motors. When the drivers 6 a and 6 b areattached to the actuators, the actuators engage with the sliders of thedrivers 6 a and 6 b. When the actuators are actuated, the sliders slideso as to apply a traction force F to the manipulation wires 22 a and 22b.

When manually-operated masters are attached to the drivers 6 a and 6 b,operation sections engage with the sliders of the drivers 6 a and 6 b.The sliders slide in accordance with a force applied by the surgeon A soas to apply a traction force F to the manipulation wires 22 a and 22 b.

The relay unit 27 is provided with an insertion port 29 for inserting asurgical device into a forceps channel (not shown) having an opening inan end surface thereof and extending in the longitudinal direction ofthe insertion part 7.

As shown in FIG. 1, the master device 2 is an orthomorphic input devicehaving joints equal in number to the number of joints in the bendablesection 10 of the endoscope 5. Each joint is equipped with a detector(not shown), such as an encoder, for detecting the flexion angle of thejoint. When the surgeon A holds and moves the distal end, the detectorsdetect and output flexion-angle signals of the joints of the masterdevice 2.

The controller 4 controls the drivers 6 a and 6 b so as to make theflexion angles of the joints of the master device 2, indicated by theflexion-angle signals output from the master device 2, equal to theflexion angles of the flexure joints 11 a to 11 c and 12 a to 12 d inthe bendable section 10 of the endoscope 5.

The operation of the flexure joints 12 a to 12 d, the endoscope 5, andthe endoscope system 1 according to this embodiment having theabove-described configuration will be described below.

In order to observe and treat the inside of the body of the patient P byusing the endoscope 5 according to this embodiment, a process forinserting the endoscope 5 into the body cavity is performed by attachinga manually-operated master only to the distal-end driver 6 a that drivesthe distal-end joint group 11.

While holding and operating the manually-operated master with his/herleft hand, the surgeon A holds the insertion part 7 with his/her righthand and inserts the endoscope 5 into the body cavity based on a methodsimilar to that used for an endoscope in the related art. In this case,an image of the state in the body cavity is captured by actuating theendoscope 5 and is displayed on the monitor 25. The surgeon A operatesthe manually-operated master while viewing the monitor 25 so as to drivethe distal-end joint group 11, and inserts the insertion part 7 into thebody cavity until the distal end section 9 of the endoscope 5 is broughtclose to an affected area.

In this state, a drive source 28 or a manually-operated master is notattached to the basal-end driver 6 b that drives the basal-end jointgroup 12. Thus, the basal-end joint group 12 moves by passivelyfollowing the movement of the distal-end joint group 11. This preventsthe insertion process from being hindered by the basal-end joint group12.

When the distal end section 9 of the insertion part 7 is disposed closeto an affected area, a drive source 28 is attached to the basal-enddriver 6 b so as to switch from the manually-operated master to thedrive source 28. The surgeon A then operates the master device 2.

The endoscope 5 according to this embodiment has four flexure joints 12a to 12 d, which serve as the basal-end joint group 12 and canaltogether be flexed by ±240°. Therefore, the bendable section 10 can bebent into a U-shape so that the distal-end surface of the endoscope 5can be oriented toward the rear. Moreover, since there is still room formovement of the flexure joints 12 a to 12 d even in the state where thebendable section 10 is bent in a U-shape, the distal end section 9 ofthe insertion part 7 can advance or recede. As a result, this isadvantageous in that the distal-end surface of the insertion part 7 canbe oriented toward an easily observable or treatable position not onlyfor an affected area located toward the front in the direction in whichthe endoscope 5 is inserted into the body cavity but also for anaffected area located in the opposite direction, such as an affectedarea behind a fold.

In order to cause the flexure joint 12 d according to this embodiment toflex as shown in FIG. 5, a traction force F is applied by the drivesource 28 to the manipulation wire 22 a, which is to be disposed at theinner side of the flexed joint, of the two manipulation wires 22 a and22 b routed toward the basal end of the flexible section 8 via the guidesheaths 21 a and 21 b, thereby pulling the manipulation wire 22 a. Onthe other hand, the other manipulation wire 22 b, which is to bedisposed at the outer side of the flexed joint, is fed by an amountaccording to the path length of the outer side of the flexed joint.

Accordingly, the traction force F transmitted to the distal end of themanipulation wire 22 a causes tension to occur in the manipulation wire22 a between the pulley 20 a on the link member 13 e and the fixationsection 26 a on the link member 13 d. This causes the link members 13 dand 13 e and the segments 15 a to 15 d therebetween to relativelyswivel, so that the pulley 20 a on the link member 13 e and the fixationsection 26 a on the link member 13 d are brought closer to each other,whereby the flexure joint 12 d is flexed. The flexure joints 12 a to 12c can be flexed in a similar manner.

In this case, in the flexure joints 12 a to 12 d, the guide sheaths 21 aand 21 b that guide the manipulation wires 22 a and 22 b from the basalend of the flexible section 8 to the link members 13 b to 13 e locatedtoward the distal end are disposed along the vicinity of the centralaxes of the flexure joints 12 a to 12 d. Therefore, the radii ofcurvature of the guide sheaths 21 a and 21 b when the flexure joints 12a to 12 d are flexed can be maintained at larger values than in a normalcase where the sheaths are disposed at the inner side by being set nearthe outer peripheries of the joints.

Furthermore, the guide sheaths 21 a and 21 b are disposed along thevicinity of the central axes of the flexure joints 12 a to 12 d even ina case where the bending direction is inverted. Thus, the variation inthe radii of curvature of the sheaths is reduced, and variations in theresistance force against bending, which is generated due to the rigidityof the sheaths, can be minimized.

The guide sheaths 21 a and 21 b each have a larger diameter and higherbending rigidity than the manipulation wire 22 a disposed at the innerside. This is advantageous in that, by maintaining the radii ofcurvature during flexion at large values, the traction force F requiredfor flexion can be reduced, and variations in the required tractionforce F can be minimized.

Furthermore, since the manipulation wires 22 a and 22 b are turned backby the pulleys 20 a and 20 b to make a U-turn, the manipulation wires 22a and 22 b move smoothly with low friction when a traction force F isapplied thereto for flexing the flexure joints 12 a to 12 d. Thus, thetraction force F for causing the flexure joints 12 a to 12 d to flex canbe further reduced.

Moreover, since the distal ends of the manipulation wires 22 a and 22 bturned back by the pulleys 20 a and 20 b are fixed to the fixationsections 26 a and 26 b located far, in the radial direction, from theaxes 16 e of the link members 13 a to 13 d serving as the first members,large moment can be generated by the traction force F applied to themanipulation wires 22 a and 22 b, which is advantageous in that theflexure joints 12 a to 12 d can be flexed efficiently.

Furthermore, in this embodiment, the link members 13 b to 13 e haveidentical pulleys 20 a and 20 b disposed at identical positions and inidentical orientations in the circumferential direction and the radialdirection, thereby achieving commonality of the link members 13 b to 13e and reducing the number of types of components.

Furthermore, the endoscope 5 according to this embodiment having theabove-described flexure joints 12 a to 12 d can minimize changes in thetraction force F in accordance with the degree of flexion of the flexurejoints 12 a to 12 d. This is advantageous in that the controllabilityusing the drivers 6 a and 6 b can be improved.

Moreover, with the endoscope system 1 according to this embodiment, thecontrollability of the endoscope 5 is improved so that theresponsiveness of the slave device 3 to the operation of the masterdevice 2 is improved, which is advantageous in that improvedmanipulability can be achieved.

In the flexure joints 12 a to 12 d according to this embodiment, thepair of guide sheaths 21 a and 21 b that guide the pair of manipulationwires 22 a and 22 b for bending the flexure joints 12 a to 12 d towardboth sides are disposed adjacent to each other with the axes 16 a to 16e interposed therebetween. Alternatively, if space permits, the pair ofguide sheaths 21 a and 21 b are preferably arranged in a single line onthe axes 16 a to 16 e. Thus, when the flexure joints 12 a to 12 d are tobe flexed toward both sides, all radii of curvature of the guide sheaths21 a and 21 b can be made the same so that the path lengths of thesheaths become fixed, thereby eliminating the need to warp the sheathsand minimizing the traction force required for flexion.

Furthermore, although the pulleys 20 a and 20 b are used as turnaroundsections that cause the manipulation wires 22 a and 22 b to make aU-turn in this embodiment, U-shaped tubular members 30 a and 30 b thatare composed of a high-rigidity material and that allow the manipulationwires 22 a and 22 b to extend therethrough to make a U-turn may be usedas an alternative, as shown in FIG. 9. With this configuration, themanipulation wires 22 a and 22 b move smoothly through the tubularmembers 30 a and 30 b while fixed curvatures are maintained by thetubular members 30 a and 30 b, so that the bending operation can beperformed with a small traction force F. Moreover, with this structurethat does not have movable components like the rotating pulleys 20 a and20 b, increased durability can be achieved.

Furthermore, in this embodiment, the positions of the pulleys 20 a and20 b are identical among all of the link members 13 b to 13 e serving asthe second members. Alternatively, as shown in FIGS. 10A, 10B, and 10C,the positions of the pulleys 20 a and 20 b may be varied in thecircumferential direction among different link members 13 b to 13 d. Thediagonal lines indicate the guide sheaths 21 a and 21 b that guide themanipulation wires 22 a and 22 b to the pulleys 20 a and 20 b of thecorresponding link members 13 b to 13 d. Consequently, the openings atthe distal ends of the guide sheaths 21 a and 21 b can be brought closeto the pulleys 20 a and 20 b, which is advantageous in that the routingof the manipulation wires 22 a and 22 b from the guide sheaths 21 a and21 b can be performed without difficulty.

Furthermore, in this embodiment, the pair of pulleys 20 a and 20 b aredisposed at symmetric positions at the opposite sides of the axis 16 a.Alternatively, as shown in FIG. 11, the pair of pulleys 20 a and 20 bmay be shifted in the thickness direction so as to partially overlapeach other in the radial direction. With this arrangement, largediameters can be ensured for the pulleys 20 a and 20 b, so that theradii of curvature of the manipulation wires 22 a and 22 b to be turnedback can be increased, thereby reducing the load on the manipulationwires 22 a and 22 b.

Furthermore, in this embodiment, the pulleys 20 a and 20 b in all of theflexure joints 12 a to 12 d cause the manipulation wires 22 a and 22 bto make a U-turn. Alternatively, as shown in FIG. 12, the flexure joint12 a located closest to the distal end may employ a method of pullingthe link member 13 b toward the basal end by using manipulation wires 22a and 22 b extended toward the distal end from the guide sheaths 21 aand 21 b fixed to the link member 13 a at the end of the flexiblesection 8. With such a configuration, the guide sheaths 21 a and 21 bcan be disposed at positions where they do not bend in accordance withthe flexion of the flexure joint 12 a, so that the pulleys 20 a and 20 bcan be omitted, thereby achieving a simplified structure.

Furthermore, in this embodiment, the basal-end joint group 12 isconstituted of four flexure joints 12 a to 12 d having substantiallyparallel axes 14 a to 14 d. Alternatively, as shown in FIG. 13, abasal-end joint group 12 in which the flexing direction alternatelychanges in orthogonal directions may be employed. In this case, as shownin FIGS. 14A, 14B, and 14C, the positions of the guide sheaths 21 a and21 b may be identical among the link members 13 b to 13 e, and the linkmembers 13 b to 13 e with the pulleys 20 a and 20 b disposed atdifferent positions may be alternately disposed. As another alternative,as shown in FIGS. 15A, 15B, and 15C, the phases of the identical linkmembers 13 b to 13 e may be varied by 90°. Reference sign 31 denotes achannel through which, for example, wires with higher rigidity than theguide sheaths 21 a and 21 b extend.

Furthermore, in this embodiment, the endoscope 5 having the basal-endjoint group 12 with the four series-connected flexure joints 12 a to 12d is described as an example. Alternatively, as shown in FIG. 16, theembodiment may be applied to a manipulator 5 having a single flexurejoint 12 a.

Furthermore, the segments 15 a to 15 d are described as having thethrough-holes 24 a and 24 b through which the manipulation wires 22 aand 22 b extend. Alternatively, as shown in FIGS. 17 and 18, thepass-through sections through which the manipulation wires 22 a and 22 bextend may have long holes 32 a and 32 b or grooves 33 a and 33 bextending in a direction orthogonal to the axes 16 a to 16 e.

As shown in FIG. 16, in a case where the through-holes 24 a and 24 bhave an inside diameter that is slightly larger than the outsidediameter of the manipulation wires 22 a and 22 b, the segments 15 a to15 d swivel when the flexure joints 12 a to 12 d are flexed, causing thethrough-holes 24 a and 24 b provided in the segments 15 a to 15 d to bearranged along curved lines. Thus, each manipulation wire 22 a or 22 bextending through the through-holes 24 a or 24 b is bent so as toconnect the through-holes 24 a or 24 b.

In this case, since the tension generated in the manipulation wires 22 aand 22 b increases in accordance with the magnitude of the tractionforce F, the manipulation wires 22 a and 22 b become pressed against theinner surfaces of the through-holes 24 a and 24 b, thus resulting inincreased friction. In contrast, as shown in FIGS. 17 and 18, by formingthe pass-through sections as long holes 32 a and 32 b or grooves 33 aand 33 b, deformation of the manipulation wires 22 a and 22 b in theradial direction is reduced when the flexure joints 12 a to 12 d areflexed, as shown in FIG. 19, so that the frictional force between themanipulation wires 22 a and 22 b and the inner surfaces of the longholes 32 a and 32 b or the grooves 33 a and 33 b is reduced even whenthe tension increases, thereby ensuring smooth movement of themanipulation wires 22 a and 22 b. FIG. 19 illustrates a flexed state ina case where the pass-through sections are the grooves 33 a and 33 b.

Although the endoscope 5 and the endoscope system 1 are described asexamples of a manipulator and a manipulator system in this embodiment,the embodiment may alternatively be applied to other types ofmanipulators and manipulator systems, such as a surgical device.

Furthermore, although flexure joints provided in the endoscope 5 in theslave device 3 are described as an example, the embodiment mayalternatively be applied to flexure joints provided in a manualendoscope.

Furthermore, examples of the manipulation wires 22 a and 22 b includesolid wires, stranded wires, braided wires, and plates.

Consequently, the above-described embodiment derives the followingsolutions.

A first aspect of the present invention provides a joint mechanismincluding a tubular first member having a through-hole extending along acentral axis; a second member disposed at a distal end of the firstmember and swivelable relative to the first member about a swivel axisintersecting the central axis; a flexible, tubular guide sheathextending near the central axis of the through-hole in the first memberand a distal end of which is fixed to the second member; a manipulationwire introduced toward the distal end of the guide sheath via the guidesheath; and a turnaround section that is provided in the second memberat a position decentered from the swivel axis in a radial direction andthat causes the manipulation wire introduced from the first member viathe guide sheath to make a U-turn toward the first member. A distal endof the manipulation wire caused to make a U-turn at the turnaroundsection is fixed to the first member at a position decentered from theswivel axis in the radial direction.

According to this aspect, when a traction force acting toward the basalend is applied to the basal end of the manipulation wire, the tractionforce propagates through the manipulation wire to the distal end thereofso as to act in a direction in which the turnaround section that causesthe manipulation wire to make a U-turn and the first member to which thedistal end of the manipulation wire is fixed are brought closer to eachother. Since the positions where the turnaround section and themanipulation wire are fixed to the first member are decentered from theswivel axis in the radial direction, moment according to the decenteredamount and the magnitude of the traction force is generated, so that thesecond member can be made to swivel relative to the first member in onedirection about the swivel axis.

In this case, when the second member swivels relative to the firstmember, the guide sheath whose distal end is fixed to the second memberalso bends in the swiveling direction of the second member. However,since the guide sheath extends near the central axis of the jointmechanism and the manipulation wire alone is disposed near the outerperiphery of the joint mechanism, the guide sheath, which has relativelyhigh rigidity, can be prevented from being bent with an extremely smallradius of curvature, thereby allowing for bending with a small tractionforce. As a result, reduced device size and improved controllability canbe achieved.

In the above aspect, the turnaround section may be a pulley around whichthe manipulation wire is wound to cause the manipulation wire to make aU-turn.

Accordingly, when causing the second member to swivel relative to thefirst member by applying a traction force to the manipulation wire, thepulley is rotated so that the manipulation wire can be moved with asmall frictional force, thereby allowing for bending with an evensmaller traction force.

Furthermore, in the above aspect, the turnaround section may be asubstantially U-shaped tubular member that allows the manipulation wireto extend therethrough so as to cause the manipulation wire to make aU-turn.

Accordingly, when causing the second member to swivel relative to thefirst member by applying a traction force to the manipulation wire, themanipulation wire can be moved within the tubular member while a fixedradius of curvature is maintained by the tubular member, therebyallowing for bending with a stable traction force.

Furthermore, in the above aspect, the guide sheath, the manipulationwire, and the turnaround section may include a pair of guide sheaths, apair of manipulation wires, and a pair of turnaround sections,respectively, so as to cause the second member to swivel relative to thefirst member in two directions about the swivel axis.

Accordingly, the second member can be made to swivel relative to thefirst member in one direction by applying a traction force to one of themanipulation wires, and the second member can be made to swivel relativeto the first member in the other direction by applying a traction forceto the other manipulation wire. In the case where the second member ismade to swivel relative to the first member in two directions about theswivel axis in this manner, the advantage of making the guide sheathextend near the central axis is high particularly in that the guidesheath can be prevented from being bent with an extremely small radiusof curvature for both of the two directions.

Furthermore, in the above aspect, the pair of turnaround sections may beprovided to cause the pair of manipulation wires to make a U-turn atpositions partially overlapping each other in the radial direction.

Accordingly, the diameter of the turnaround sections can be made largerthan the radius of the second member so that when the manipulation wiresare caused to make a U-turn, a frictional force occurring between themanipulation wires and the turnaround sections can be reduced.

Furthermore, in the above aspect, the joint mechanism may furtherinclude one or more intermediate members provided between the firstmember and the second member and connected in a swivelable manner abouttwo or more intermediate axes that are parallel to each other.

Accordingly, by causing the intermediate members to swivel about theintermediate axes, the positions of the intermediate axes are moved inthe swiveling direction, so that a large overall swivel-angle range ofthe second member relative to the first member can be ensured.

Furthermore, in the above aspect, each intermediate member may beprovided with a sheath pass-through hole that allows the guide sheath toextend therethrough and a wire pass-through section that allows themanipulation wire to extend therethrough. Moreover, the wirepass-through section may be a long hole or a cutout extending in adirection orthogonal to the intermediate axes.

Accordingly, the manipulation wire is moved through the wirepass-through section defined by a long hole or a cutout in the directionorthogonal to the intermediate axes in accordance with the swivel angleof the second member relative to the first member, so that a forceapplied to the manipulation wire in the lateral direction can bereleased as much as possible, whereby friction occurring when themanipulation wire moves can be reduced. Consequently, the second membercan be made to swivel relative to the first member by simply applying asmall traction force to the manipulation wire.

A second aspect of the present invention provides a manipulatorincluding two or more series-connected joint mechanisms described above.

According to this aspect, an even larger overall bending-angle range canbe ensured.

In the above aspect, the turnaround sections provided in the respectivejoint mechanisms may be disposed at substantially identical positions inthe radial direction and a circumferential direction of the secondmembers.

Accordingly, the plurality of first members, the plurality of secondmembers, and the plurality of turnaround sections can respectively haveidentical shapes, thereby achieving commonality of components. Moreover,the turnaround sections and the distal ends of the manipulation wires,to which a traction force is to be applied, are fixed at identicalpositions so that uniform controllability can be achieved for all of thejoint mechanisms.

Furthermore, in the above aspect, the turnaround sections provided inthe respective joint mechanisms may be disposed at substantiallyidentical positions in the radial direction of the second members but atdifferent positions in a circumferential direction.

Accordingly, the routing of the manipulation wires from the openings atthe distal ends of the guide sheaths toward the turnaround sections canbe performed without difficulty while maintaining substantiallyidentical fixation positions for the turnaround sections and the distalends of the manipulation wires, to which a traction force is to beapplied.

A third aspect of the present invention provides a manipulator includinga tubular manipulator body, a basal-end joint unit provided at a distalend of the manipulator body, and a distal-end joint unit connected inseries to a distal end of the basal-end joint unit and equipped with atleast one joint mechanism described above. The basal-end joint unitincludes a swivel member connected to the manipulator body in aswivelable manner about a swivel axis, a tubular guide sheath whoseopening at a distal end thereof is fixed to the manipulator body, and amanipulation wire that is introduced via the guide sheath and protrudesfrom the opening at the distal end of the guide sheath and a distal endof which is fixed to a position decentered from the swivel axis of theswivel member in a radial direction.

According to this aspect, in the basal-end joint unit located closest tothe manipulator body, the swivel member can be made to swivel relativeto the manipulator body by pulling the swivel member from themanipulator body side toward the basal end. Consequently, the number ofguide sheaths extending through the basal-end joint unit can be reducedso that the rigidity can be reduced, whereby the basal-end joint unitcan be bent with a small traction force.

A fourth aspect of the present invention provides a manipulatorincluding a tubular manipulator body having a through-hole extendingalong a central axis; a swivel member disposed at a distal end of themanipulator body and swivelable relative to the manipulator body about aswivel axis intersecting the central axis; a flexible, tubular guidesheath extending near the central axis of the through-hole in themanipulator body and a distal end of which is fixed to the swivelmember; a manipulation wire introduced toward the distal end of theguide sheath via the guide sheath; and a turnaround section that isprovided in the swivel member and that causes the manipulation wireintroduced from the manipulator body via the guide sheath to make aU-turn toward the manipulator body. A distal end of the manipulationwire caused to make a U-turn at the turnaround section is fixed to themanipulator body at a position decentered from the swivel axis in theradial direction.

According to this aspect, even in a manipulator having a single jointmechanism disposed at the distal end of the manipulator body, a tractionforce can be applied to a position sufficiently decentered from theswivel axis in the radial direction by causing the manipulation wire tomake a U-turn and fixing the distal end thereof to the manipulator body,whereby the swivel member can be made to swivel with a small tractionforce.

A fifth aspect of the present invention provides a manipulator systemincluding the above-described manipulator, a slave device equipped witha driver that drives the manipulator, a master device equipped with anoperation section to be operated by an operator, and a controller thatcontrols the driver of the slave device based on an input signal inputvia the operation section of the master device.

Advantageous Effects of Invention

The present invention is advantageous in that it achieves bendabilitywith a small traction force, reduced device size, and improvedcontrollability.

REFERENCE SIGNS LIST

-   A surgeon (operator)-   1 endoscope system (manipulator system)-   2 master device-   3 slave device-   4 controller-   5 endoscope (manipulator)-   8 flexible section (manipulator body)-   12 a to 12 d flexure joints (joint mechanism)-   13 a link member (first member)-   13 b link member (second member)-   14 a swivel axis-   15 a to 15 d intermediate members-   16 a to 16 e intermediate axes-   17 through-hole-   18 through-hole (sheath pass-through hole)-   20 a, 20 b pulleys (turnaround sections)-   21 a, 21 b guide sheaths-   22 a, 22 b manipulation wires-   24 a through-hole (wire pass-through sections)-   30 a, 30 b tubular members (turnaround sections)-   32 a, 32 b long holes (wire pass-through sections)-   33 a, 33 b grooves (wire pass-through sections)

1. A joint mechanism comprising: a tubular first member having athrough-hole extending along a central axis; a second member disposed ata distal end of the first member and swivelable relative to the firstmember about a swivel axis intersecting the central axis; a flexible,tubular guide sheath extending near the central axis of the through-holein the first member and a distal end of which is fixed to the secondmember; a manipulation wire introduced toward the distal end of theguide sheath via the guide sheath; and a turnaround section that isprovided in the second member at a position decentered from the swivelaxis in a radial direction and that causes the manipulation wireintroduced from the first member via the guide sheath to make a U-turntoward the first member, wherein a distal end of the manipulation wirecaused to make a U-turn at the turnaround section is fixed to the firstmember at a position decentered from the swivel axis of the first memberin the radial direction.
 2. The joint mechanism according to claim 1,wherein the turnaround section is a pulley around which the manipulationwire is wound to cause the manipulation wire to make a U-turn.
 3. Thejoint mechanism according to claim 1, wherein the turnaround section isa substantially U-shaped tubular member that allows the manipulationwire to extend therethrough so as to cause the manipulation wire to makea U-turn.
 4. The joint mechanism according to claim 1, wherein the guidesheath, the manipulation wire, and the turnaround section include a pairof guide sheaths, a pair of manipulation wires, and a pair of turnaroundsections, respectively, so as to cause the second member to swivelrelative to the first member in two directions about the swivel axis. 5.The joint mechanism according to claim 4, wherein the pair of turnaroundsections are provided to cause the pair of manipulation wires to make aU-turn at positions partially overlapping each other in the radialdirection.
 6. The joint mechanism according to claim 1, furthercomprising one or more intermediate members provided between the firstmember and the second member and connected in a swivelable manner abouttwo or more intermediate axes that are parallel to each other.
 7. Thejoint mechanism according to claim 6, wherein each intermediate memberis provided with a sheath pass-through hole that allows the guide sheathto extend therethrough and a wire pass-through section that allows themanipulation wire to extend therethrough, and wherein the wirepass-through section is a long hole or a cutout extending in a directionorthogonal to the intermediate axes.
 8. A manipulator including two ormore series-connected joint mechanisms, wherein the two or moreseries-connected joint mechanisms each comprise: a tubular first memberhaving a through-hole extending along a central axis; a second memberdisposed at a distal end of the first member and swivelable relative tothe first member about a swivel axis intersecting the central axis; aflexible, tubular guide sheath extending near the central axis of thethrough-hole in the first member and a distal end of which is fixed tothe second member; a manipulation wire introduced toward the distal endof the guide sheath via the guide sheath; and a turnaround section thatis provided in the second member at a position decentered from theswivel axis in a radial direction and that causes the manipulation wireintroduced from the first member via the guide sheath to make a U-turntoward the first member, wherein a distal end of the manipulation wirecaused to make a U-turn at the turnaround section is fixed to the firstmember at a position decentered from the swivel axis of the first memberin the radial direction.
 9. The manipulator according to claim 8,wherein the turnaround sections provided in the respective jointmechanisms are disposed at substantially identical positions in theradial direction and a circumferential direction of the second members.10. The manipulator according to claim 8, wherein the turnaroundsections provided in the respective joint mechanisms are disposed atsubstantially identical positions in the radial direction of the secondmembers but at different positions in a circumferential direction.
 11. Amanipulator comprising: a tubular manipulator body; a basal-end jointunit provided at a distal end of the manipulator body; and a distal-endjoint unit connected in series to a distal end of the basal-end jointunit and equipped with at least one joint mechanism, wherein the atleast one joint mechanism comprises: a tubular first member having athrough-hole extending along a central axis; a second member disposed ata distal end of the first member and swivelable relative to the firstmember about a swivel axis intersecting the central axis; a flexible,tubular guide sheath extending near the central axis of the through-holein the first member and a distal end of which is fixed to the secondmember; a manipulation wire introduced toward the distal end of theguide sheath via the guide sheath; and a turnaround section that isprovided in the second member at a position decentered from the swivelaxis in a radial direction and that causes the manipulation wireintroduced from the first member via the guide sheath to make a U-turntoward the first member, wherein a distal end of the manipulation wirecaused to make a U-turn at the turnaround section is fixed to the firstmember at a position decentered from the swivel axis of the first memberin the radial direction, and wherein the basal-end joint unit comprises:a swivel member connected to the manipulator body in a swivelable mannerabout a swivel axis; a tubular guide sheath whose opening at a distalend thereof is fixed to the manipulator body; and a manipulation wirethat is introduced via the guide sheath and protrudes from the openingat the distal end of the guide sheath and a distal end of which is fixedto a position decentered from the swivel axis of the swivel member in aradial direction.
 12. A manipulator comprising: a tubular manipulatorbody having a through-hole extending along a central axis; a swivelmember disposed at a distal end of the manipulator body and swivelablerelative to the manipulator body about a swivel axis intersecting thecentral axis; a flexible, tubular guide sheath extending near thecentral axis of the through-hole in the manipulator body and a distalend of which is fixed to the swivel member; a manipulation wireintroduced toward the distal end of the guide sheath via the guidesheath; and a turnaround section that is provided in the swivel memberand that causes the manipulation wire introduced from the manipulatorbody via the guide sheath to make a U-turn toward the manipulator body,wherein a distal end of the manipulation wire caused to make a U-turn atthe turnaround section is fixed to the manipulator body at a positiondecentered from the swivel axis in the radial direction.
 13. Amanipulator system comprising: a manipulator including two or moreseries-connected joint mechanisms; a slave device equipped with a driverthat drives the manipulator; a master device equipped with an operationsection to be operated by an operator; and a controller that controlsthe driver of the slave device based on an input signal input via theoperation section of the master device, wherein the two or moreseries-connected joint mechanisms each comprise: a tubular first memberhaving a through-hole extending along a central axis; a second memberdisposed at a distal end of the first member and swivelable relative tothe first member about a swivel axis intersecting the central axis; aflexible, tubular guide sheath extending near the central axis of thethrough-hole in the first member and a distal end of which is fixed tothe second member; a manipulation wire introduced toward the distal endof the guide sheath via the guide sheath; and a turnaround section thatis provided in the second member at a position decentered from theswivel axis in a radial direction and that causes the manipulation wireintroduced from the first member via the guide sheath to make a U-turntoward the first member, wherein a distal end of the manipulation wirecaused to make a U-turn at the turnaround section is fixed to the firstmember at a position decentered from the swivel axis of the first memberin the radial direction.
 14. A manipulator system comprising: amanipulator including a tubular manipulator body, a basal-end joint unitprovided at a distal end of the manipulator body, and a distal-end jointunit connected in series to a distal end of the basal-end joint unit andequipped with at least one joint mechanism; a slave device equipped witha driver that drives the manipulator; a master device equipped with anoperation section to be operated by an operator; and a controller thatcontrols the driver of the slave device based on an input signal inputvia the operation section of the master device, wherein the at least onejoint mechanism comprises: a tubular first member having a through-holeextending along a central axis; a second member disposed at a distal endof the first member and swivelable relative to the first member about aswivel axis intersecting the central axis; a flexible, tubular guidesheath extending near the central axis of the through-hole in the firstmember and a distal end of which is fixed to the second member; amanipulation wire introduced toward the distal end of the guide sheathvia the guide sheath; and a turnaround section that is provided in thesecond member at a position decentered from the swivel axis in a radialdirection and that causes the manipulation wire introduced from thefirst member via the guide sheath to make a U-turn toward the firstmember, wherein a distal end of the manipulation wire caused to make aU-turn at the turnaround section is fixed to the first member at aposition decentered from the swivel axis of the first member in theradial direction, and wherein the basal-end joint unit comprises: aswivel member connected to the manipulator body in a swivelable mannerabout a swivel axis; a tubular guide sheath whose opening at a distalend thereof is fixed to the manipulator body; and a manipulation wirethat is introduced via the guide sheath and protrudes from the openingat the distal end of the guide sheath and a distal end of which is fixedto a position decentered from the swivel axis of the swivel member in aradial direction.
 15. A manipulator system comprising: a manipulator; aslave device equipped with a driver that drives the manipulator; amaster device equipped with an operation section to be operated by anoperator; and a controller that controls the driver of the slave devicebased on an input signal input via the operation section of the masterdevice, wherein the manipulator comprises: a tubular manipulator bodyhaving a through-hole extending along a central axis; a swivel memberdisposed at a distal end of the manipulator body and swivelable relativeto the manipulator body about a swivel axis intersecting the centralaxis; a flexible, tubular guide sheath extending near the central axisof the through-hole in the manipulator body and a distal end of which isfixed to the swivel member; a manipulation wire introduced toward thedistal end of the guide sheath via the guide sheath; and a turnaroundsection that is provided in the swivel member and that causes themanipulation wire introduced from the manipulator body via the guidesheath to make a U-turn toward the manipulator body, wherein a distalend of the manipulation wire caused to make a U-turn at the turnaroundsection is fixed to the manipulator body at a position decentered fromthe swivel axis in the radial direction.